VITAMIN C CONTENT OF VARIOUS CITRUS JUICES. Alexandra. Throughout this experiment, the Vitamin C contents of orange juice, lemon juice, and grapefruit juice were determined by means of titration. In this experiment, the process of titration involved the addition of an iodine solution to a solution composed of juice, hydrochloric acid, and starch solution. When added to the solution of juice, the iodine solution immediately reacted with the ascorbic acid present in the solution, but when this Vitamin C was depleted, the iodine solution was free to react with the starch indicator, making the solution drastically change color. It was found that the titration of 0.13 grams of ascorbic acid required 83.90 mL of iodine solution. This result was then used to proportionally calculate the amount of Vitamin C per 25 mL of orange juice, grapefruit juice, and lemon juice. It was found that 25 mL of orange juice contained 12.1 mg of Vitamin C, 25 mL of grapefruit juice contained 25.2 mg of Vitamin C, and 25 mL of lemon juice contained 8.29 mg of Vitamin C. In comparison with the true values for these amounts, there was a 2.42% error in the titration of orange juice, a 7.80% error in the titration of lemon juice, and a 169% error in the titration of grapefruit juice. Though the results of this experiment indicate that grapefruit juice has the highest Vitamin C content, other sources indicate that orange juice has the highest Vitamin C content.
Beginning in 1997 and coming to an end in 2007, this experiment evaluated the long-term effectiveness of Vitamins E and C in mitigating the spread of prostate cancer in middle-aged men. Throughout the experiment, men over fifty years of age with histories of prostate cancer were dealt individual doses of Vitamin E and C supplements. The participants were given 400 IU of Vitamin E every other day and 500 mg of Vitamin C daily. Conducting follow-ups with patients following eight years of this routine, the researchers found that compared with a placebo, neither the Vitamin E nor the Vitamin C supplements showed effects on the spread or containment of the prostate cancer. In addition to not affecting prostate cancer, neither vitamin displayed any effect on the spread of total cancer or cancer prevention. In the 1,943 cases of cancer reported, the results unanimously displayed that neither vitamin affected the course of colorectal, lung, or other specifically located cancers. For this reason, these data provide no support for the use of these supplements for the prevention of cancer in middle-aged and older men.
Gaziano JM, Glynn RJ, Christen WG, Kurth T, Belanger C, MacFadyen J, Bubes V, Manson JE, Sesso HD, Buring JE. 7 January 2009. The Effects of Vitamins C and E on Prostate and Total Cancer. 301(1):52-62.
Data and Calculations: Table 1--Standard Solution:
Trial Number:
Volume of Solution Used:
Mass of Vitamin C Used:
Volume of Iodine Solution Used:
1
30 mL
0.50 g
NA
2
30 mL
0.13 g
83.90 mL
Average Volume of Iodine Solution Used: 83.90 mL Table 2--Orange Juice:
Trial Number:
Volume of Juice Used:
Volume of Iodine Solution Used:
1
25 mL
27.80 mL
2
25 mL
25.20 mL
3
25 mL
25.14 mL
Average Volume of Iodine Solution Used: 26.05 mL Table 3--Grapefruit Juice:
Trial Number:
Volume of Juice Used:
Volume of Iodine Solution Used:
1
25 mL
31.40 mL
2
25 mL
22.70 mL
3
25 mL
52.55 mL
4
25 mL
55.83 mL
Average Volume of Iodine Solution Used in Trials 3 & 4: 54.19 mL Table 4--Lemon Juice:
Trial Number:
Volume of Juice Used:
Volume of Iodine Solution Used:
1
25 mL
17.60 mL
2
25 mL
16.63 mL
3
25 mL
19.27 mL
Average Volume of Iodine Solution Used: 17.83 mL
Table 5--True Values (Nutrition Data 2010):
Titration of Vitamin C in Citrus Juices
Performing a Titration
Juices Prior to Titration
Abstract:VITAMIN C CONTENT OF VARIOUS CITRUS JUICES. Alexandra. Throughout this experiment, the Vitamin C contents of orange juice, lemon juice, and grapefruit juice were determined by means of titration. In this experiment, the process of titration involved the addition of an iodine solution to a solution composed of juice, hydrochloric acid, and starch solution. When added to the solution of juice, the iodine solution immediately reacted with the ascorbic acid present in the solution, but when this Vitamin C was depleted, the iodine solution was free to react with the starch indicator, making the solution drastically change color. It was found that the titration of 0.13 grams of ascorbic acid required 83.90 mL of iodine solution. This result was then used to proportionally calculate the amount of Vitamin C per 25 mL of orange juice, grapefruit juice, and lemon juice. It was found that 25 mL of orange juice contained 12.1 mg of Vitamin C, 25 mL of grapefruit juice contained 25.2 mg of Vitamin C, and 25 mL of lemon juice contained 8.29 mg of Vitamin C. In comparison with the true values for these amounts, there was a 2.42% error in the titration of orange juice, a 7.80% error in the titration of lemon juice, and a 169% error in the titration of grapefruit juice. Though the results of this experiment indicate that grapefruit juice has the highest Vitamin C content, other sources indicate that orange juice has the highest Vitamin C content.
Link to Scientific Journal Article:
http://jama.ama-assn.org/cgi/content/short/301/1/52
Summary of Scientific Journal Article:
Beginning in 1997 and coming to an end in 2007, this experiment evaluated the long-term effectiveness of Vitamins E and C in mitigating the spread of prostate cancer in middle-aged men. Throughout the experiment, men over fifty years of age with histories of prostate cancer were dealt individual doses of Vitamin E and C supplements. The participants were given 400 IU of Vitamin E every other day and 500 mg of Vitamin C daily. Conducting follow-ups with patients following eight years of this routine, the researchers found that compared with a placebo, neither the Vitamin E nor the Vitamin C supplements showed effects on the spread or containment of the prostate cancer. In addition to not affecting prostate cancer, neither vitamin displayed any effect on the spread of total cancer or cancer prevention. In the 1,943 cases of cancer reported, the results unanimously displayed that neither vitamin affected the course of colorectal, lung, or other specifically located cancers. For this reason, these data provide no support for the use of these supplements for the prevention of cancer in middle-aged and older men.
Gaziano JM, Glynn RJ, Christen WG, Kurth T, Belanger C, MacFadyen J, Bubes V, Manson JE, Sesso HD, Buring JE. 7 January 2009. The Effects of Vitamins C and E on Prostate and Total Cancer. 301(1):52-62.
Data and Calculations:
Table 1--Standard Solution:
Average Volume of Iodine Solution Used: 83.90 mL
Table 2--Orange Juice:
Average Volume of Iodine Solution Used: 26.05 mL
Table 3--Grapefruit Juice:
Average Volume of Iodine Solution Used in Trials 3 & 4: 54.19 mL
Table 4--Lemon Juice:
Average Volume of Iodine Solution Used: 17.83 mL
Table 5--True Values (Nutrition Data 2010):
Results: